Copper base alloys



United States Patent 3,234,014 COPPER BASE ALLOYS Charles D. McLain, Alton, Ill., and Carl J. Hechinger, St. Louis, Mo., assignors to Olin Mathieson Chemical Corporation, a corporation of Virginia No Drawing. Filed Oct. 23, 1963, Ser. No. 318,200 3 Claims. (Cl. 75--153) The present invention relates to improved copper base alloys containing nickel, iron, manganese and zinc. The alloys to which the present invention relates are known generally as nickel silvers and find extensive use in industry in, for example: springs, telephone, radio and television switch, relays and contacts; spring washers; diaphragms; jewelry; cartridges for ball point pens; etc.

It is an object of the present invention to provide new and improved copper base alloys.

It is a further object of the present invention to provide new and improved copper base alloys of the class known as nickel silvers, characterized by high strength at least comparable to commercially available alloys and further characterized by cost significantly lower than commercially available nickel silvers.

Further objects and advantages of the present invention will appear hereinafter.

In accordance with the present invention it has now been found that the foregoing objects and advantages may be readily accomplished and new and improved copper base alloys obtained which consist essentially of from 48 to 54 percent by weight'ofcopper, from 3.0 to 6.0 percent by weight of nickel, from 1.5 to 2.5 percent by weight of iron, from 7.5 to 8.5 percent by Weight of manganese, and the remainder zinc. It has been found that optimum results are obtained with from 52.0 to 54.0 percent by weight of copper and 3.0 to 5.0 percent by weight of nickel, with iron, manganese and zinc contents as above.

The alloys of the present invention are characterized by physical properties at least comparable to commercially available, high strength nickel silvers, such as alloy 178, but with significantly lower cost. This is a highly significant development since for numerous applications a high strength nickel silver is desired but for economic con siderations a lower cost alloy is dictated, for example, in such products as springs which require excellent strength and fatigue characteristics. Thus, the present invention solves this long standing problem and provides such a low cost, high strength alloy.

In accordance with the present invention the ranges of ingredients must critically be within the aforesaid values. For example, lowering the copper content below 48 percent by weight results in decreased ductility and formation of an undesirable second phase; whereas, increase in copper content above 54 percent by weight causes a loss in strength and a higher basic metal cost. Similarly, zinc in amounts greater than indicated above causes a decrease in ductility and enhances the formation of an unwanted second phase; whereas, lowering of the zinc content causes a decrease in the strength of the alloy.

Nickel in amounts greater than 6 percent renders the alloy unsusceptible to cold rolling by standard mill practices and in addition increases the basic metal cost. When nickel is present in less than three percent a lessening in strength results.

The iron content of the alloy is critically maintained in the range 1.5 to 2.5 percent. This ratio gives the optimum strength to ductility ratio. Any deviation from this ratio affects this ratio in a deleterious manner.

The manganese should preferably be added as ferro manganese and therefore its actual content will depend upon the iron present. A deficiency of this element, however, causes a noticeable and undesirable color change in the alloy.

3,234,14 Patented Feb. 8, 1056 Naturally, conventional impurities may be present and modifications may be made in the present composition within the foregoing critical limits, for example, lead may be added to improve machineability and non-interfering substituents may be added.

The present invention and improvements thereof will be more readily apparent from a consideration of the following illustrative examples.

EXAMPLE 1 Two alloys were prepared having the proximate compositions indicated below, one of which was an alloy of the present invention and the other was a commercial nickel silver alloy 178.

Table 1 Alloy of the Alloy 178, Element Present Percent Invention Copper 53. 0 58. 0 4.0 12.0

2. 0 0. 25 max.

8.0 0.50 max.

Remainder Remainder The physical properties of the foregoing two alloys were determined and the following results obtained:

1. Both alloys had an RF grain of 0.005 mm.

II. Tensile strength (p.s.i.):

Table 2 Percent Reduction Present Alloy Alloy 178 III. Yield strength (p.s.i.) at 0.1 percent offset:

Table 3 Percent Reduction Present; Alloy Alloy 178 IV. Percent elongation:

Table 4 Percent; Reduction Present Alloy Alloy 178 EXAMPLE 2 The basic metal cost of the alloy of the present invention as exemplified by the specific alloy of the present invention in Example 1 was compared with alloy 178 and alloy 168 (55 copper, 18% nickel, and remainder zinc) and the following values obtained:-

Table 5 Alloysz, P roximate cost per .cwt. Alloy of the present invention About $25 Alloy 168 About $35 Alloy 178 About$31 I This invention may be embodied in other forms? or carried out in other wayswithout departing from the spirit or essential Characteristics thereof. The present embodiment is therefore to be considered as in all respects illustrative and not restrictive,.-the scope of the invention being indicated by the appended claims, and all changes which come within the meaningand range of equivalency are intended to be embraced therein;

What isclairned is:

1. An alloy consisting essentially of from 2 9to.40% by weight of zinc, from 3-to 6% by weight of nickel, from 1.5 to 2.5% by weight of iron, from. 7.5 to 8.5% by weight ,of manganese and the remainder copper.

2. Ari-alloy consisting essential of from 30 to 36% by weight of zinc,.from 3 to 5% by weight ofnickel, from 1.5 s

to 2.5% by weight of iron, from 7.5 to 8.5% by weight of manganese and the remainder; copper.

3. Analloy consisting essentially of;about 33% by; weight of zinc, 4% 'by weight of nickel, 2% by; weight of iron, 8% by weight of manganeseland the remainder conper.

References Citedby the Examiner UNITED STATES PATENTS- DAVID L. RECK, Primary EJ'caminer. 

1. AN ALLOY CONSISTING ESSENTIALLY OF FROM 29 TO 40% BY WEIGHT OF ZINC, FROM 3 TO 6% BY WEIGHT OF NICKEL, FROM 1.5 TO 2.5% BY WEIGHT OF IRON, FROM 7.5 TO 8.5% BY WEIGHT OF MANGANESE AND THE REMAINDER COPPER. 